Safety-envelope



(No Model.) I v Y W. R. DALES. SAFETY ENVELOPE.

No. 516,859; Patented Mar. 20, 1894.

WITNEEEEE I INVENTD;

Ni'rn \VILLIAM R. DALES, OF ST. PAUL, MINNESOTA.

SAFETY-ENVELOPE.

SPECIFICATION forming part of Letters Patent No. 516,859, dated March20, 1894.

Application filed February 8, 1893. Serialll'o.461,450. (No model.)

and has for its object the provision of novel,-

simple and efficient means for preventing the opening of such envelopeswithout injury 7 thereto, and the fact of such opening having beenattempted concealed. As is well known, the opening of envelopes throughthe application of heat or moisture and the softening of the gumthereof, also, by the insertion of a suitable instrument, for instance,a pen-holder or pencil, beneath theirflaps, is quite a simple matter andleaves the envelope uninjured and unmarked in any way and in suchcondition that it can be readily sealed up again, without subsequentdetection. I Even wax sealing has proven ineffective, as the melting ofthe wax and the rescaling of the envelope thereafter,through the mediumof a duplicate seal, has been found comparatively easy.

'My invention consists of a safety envelope provided with registeringslits or openings in its side and bottom flaps, having its upper orsealing flap provided with an extension or tongue of sufficient lengthto permit of its being folded or doubled and gummed on one side when sofolded. Between the folds of which is placed a quantity of a fusiblesubstance or compound. Said tongue or extension, after having its gummedside moistened, being adaptedfor insertion through the slits or openingsaforesaid and to be bent upwardly inside the envelope. Bringing such,

gummed side next the bottom and side flaps, to which it adheres underpressure. Preventing access to said tongue by an opening instrument ofany kind, While. the application of heat to the envelope, for softeningthe gum which secures its parts together, will cause the fusiblesubstance or compound to melt' and spread over or saturate the envelope.Producing ineffaceable evidence of the fact that the opening of suchenvelope has been attempted.

ope-blank provided with the top and bottom flaps B Band thesideflapsOO', all gummed, as usual, the latter having a portion only oftheir opposite edges overlapped, forming the lips c c, the outermost ofwhich being also gummed to permit of its being secured to the other one,the remainder of such edges simply meeting without overlapping, as shownat 0 Said lips have each therein horizontal slits or openings 0 c oflike extent, as has, also, the lower flap B, as shown at b, said slitsor'openings all registering when the flaps in which they are located areplaced and secured by the gum'thereon in the relation shown in Fig. 2.The flap B of the envelope is provided with an extension or tongue I),having its underside, 19 when folded as in Fig, 2, gummed. Said tonguebeing of such width as to permit of its being passed through the slitsor openings mentioned,1after the gum thereof is moistened, and thrustupwardly in side the envelope, in which position, when sufficientlypressed, it adheres equally to the side flaps, at each side ofthejunction of their meeting edges. Said tongue, in its passage throughthe openings, preventing the drawing out of the side and bottom flaps,upon'the softening of the gum which secures them together, while theadherence of the same to the inner surfaces of said side flaps, preventsthe drawing out of the tongue from this position, where it cannot bereached by any outside agency for the purpose of separating it der, forthe purpose of drawing it out, will result in the destruction of saidtongue. Now, in order to guard against the undetected opening of theenvelope through the application of heat and the consequent softening ofthe gum thereof, the tongue I) is of such length as to permit of itsbeing first turned upon itself, or doubled, as shown in Figs. 2 and 4,forming a pocket for retention of a suitable fusible substance, aspal-affine, upon the inner side of one of the folds which form suchpocket is run a. narrow line of such substance, which latter serves tounite the folds of and stiffen the tongue, at the same time is concealedtherein and, upon the application of heat thereto, spreads over andsaturates the envelope and causes its discoloration, the latter resultbeing more effectively attained through the combination, with thefusible substance, of a coloring matter. So that my invention, whilepreventing the opening of envelopes without their destruction, rendersthe fact of the envelopes having been tampered with perfectly apparent,the knowledge of which operating as a warning to a party of wrongintentions.

That I claim as my invention is as follows:

In a safety envelope having registering slits or openings in its sideand bottom flaps, the combination of the sealing flap provided with anelongated transversely folded or doubled tongue, one side of which hasan adhesive surface, and a fusible substance or compound secured betweenthe folds of said tongue, the latter beingadapted forinsertion throughsaid slits or openings and for adherence equally to the inside of bothsaid side flaps, substantially as specified.

In testimony whereof I have hereunto set my hand this 4th day ofFebruary, A. D. 1893.

\VILLIAM R. DALES.

Witnesses:

WM. H. POWELL, R. DALE SPARHAWK.

